Get unique of date in data

Elastic Stack Elasticsearch
5

I ran

GET /order/_search
{
    "aggs" : {
        "genres" : {
            "terms" : { "field" : "creationDateOnlyStr" }
        }
    }
}

& it returns -

"aggregations": {
    "genres": {
      "doc_count_error_upper_bound": 0,
      "sum_other_doc_count": 0,
      "buckets": [
        {
          "key": 1483229280000,
          "key_as_string": "01-08-2017",
          "doc_count": 6450000
        },
        {
          "key": 1483228860000,
          "key_as_string": "01-01-2017",
          "doc_count": 5832001
        },
        {
          "key": 1483229040000,
          "key_as_string": "01-04-2017",
          "doc_count": 5340000
        }
      ]
    }
  }

Still not expected result